Despite important progress in knowledge about interview ‘best practice’ with child victims, few studies had yet evaluated the impact of interviewers’ personal characteristics on adherence to these ‘best practice’. This study was designed to determine whether interviewers’ personal characteristics are associated with adherence to a structured interview protocol (National Institute of Child and Human Development), the use of open-ended questions and the amount of details provided in children’s responses during investigative interviews with alleged victims of child sexual abuse. 114 interviews were scored from 13 police investigators after they followed a one-week training program. Results showed that experience, emotional intelligence, Extraversion, Agreeableness, Conscientiousness and Neuroticism were related with adherence to the protocol and ratio of open-ended questions. Cognitive abilities were related to the amount of details obtained from the child. Generalized estimating equations were used to compare relative contribution of each variable. These findings raise questions about how investigative interviewers are selected and trained.